Desiré, the photo you shared (http://www.fivedoves.com/letters/march2012/desirevdk314.htm) looked like the trials were intentionally sprayed in a pattern that would cover a large area evenly. That seams to show that the flight patterns were well planned.

 

They were filling the sky here again today with different types of trails. I would still like to know exactly what is going on.

 

many thanks for sharing the photo,

Bob